Auto Increment Mount point

I have a workflow where the volume name is a combination of several fields. If that volume name already exists the name is incremented by 1 and it is appended to the end. However, since I can't predict when volumes will be incremented and when they won't, I can't get the mount volume command to work. Since junction path only takes a literal (or user defined variable) I can't get the mount to match the volume name as simply using volume1 does nothing and $volume1 creates a user input field for volume1.